1. Field of the Invention
The present invention relates to an image acquisition device capable of reading image information recorded on film and the like.
2. Description of the Related Art
Heretofore, devices such as film scanners and the like have been known as image acquisition devices which optically read photographic negative film as a digital image.
Such film scanners generally use line or area charge-coupled devices (CCD) to photoelectrically convert the optical image of a negative film (or positive film) to read the image information of the film. When a line CCD is used, the image information of a negative film is read by moving the negative film relative to a line-type optical image reader/sensor. In such arrangements, various methods of line scanning are used to scan an optical image using mirrors and the like.
In known devices, however, the size of the CCD is smaller than the negative film, requiring the use of lenses to form a compressed optical image of the negative film on the surface of the CCD. Therefore, the digital image obtained is affected by aberrations in the lenses. For example, a square optical image may be affected by pin cushion distortion caused by distortion in a lens. Furthermore, there is a tendency for such distortion to increase when optically scanning using mirrors and the like. In order to optically reduce such distortion, it is necessary to increase the number of layers of the required lenses, thereby enlarging the device and increasing its cost.
For these reasons, methods are used to remove distortion by digitally modifying the obtained digital image in order to eliminate distortion from the digital image. Such methods include various software processing techniques comprising temporarily storing a digital image in a buffer memory, and methods using hardware to process digital images in real time. Software based methods are disadvantageous insofar as software processing requires longer time periods for higher resolution digital images which increase the amount of data to be processed. Hardware based methods are disadvantageous insofar as hardware processing requires more hardware circuits, thereby increasing the size of the device, as well as overall cost.
An object of the present invention is to eliminate the foregoing disadvantages.
A further object of the present invention is to provide an image acquisition device capable of reading images and removing distortion caused by the optical system.
A still further object of the present invention is to provide an image acquisition device capable of electrically removing distortion caused by the optical system.
Another object of the present invention is to provide an image acquisition device capable of removing distortion components included in image signals in real time.
A further object of the present invention is to provide an image acquisition device capable of removing distortion components included in image signals in real time via a simple circuit design.
These and other objects are attained by an image acquisition device capable of converting optical images formed via an optical system to a plurality of pixel signals, the image acquisition device being provided with a storage means to store correction data related to culling a plurality of pixels corresponding to the distortion inherent in an optical system, and a correction means to execute the culling of pixels in accordance with the correction data.
The aforesaid objects of the present invention are further attained by an image acquisition device comprising an optical unit for projecting an image, a reading means to obtain image data by reading an image projected by the optical unit, and a correction means to cull the image data corresponding to the distortion of the optical unit.
The aforesaid objects of the present invention are further attained by providing an image acquisition device comprising a projection lens for projecting an image, photoelectric conversion elements to read an image projected by the projection lens, moving means to move the projected image relative to the photoelectric conversion elements at constant speed in the subscan direction, memory to store correction data corresponding to the distortion of optical unit, and correction means to cull the image data in accordance with the correction data.